WO2005012727A1

WO2005012727A1 - Electromagnetic pump

Info

Publication number: WO2005012727A1
Application number: PCT/JP2004/011048
Authority: WO
Inventors: Fumihiro Yaguchi
Original assignee: Shinano Kenshi Kabushiki Kaisha
Priority date: 2003-08-01
Filing date: 2004-08-02
Publication date: 2005-02-10
Also published as: CN1846062A; CN1846062B; JP2005054638A; US20060239842A1; JP4570343B2

Abstract

An electromagnetic pump capable of highly precisely detecting an operating position of a movable element without enlarging the device. A hollow-core detecting coil (53) for detecting reciprocating motion of a movable element (10) is fitted in around a cylinder so as to be coaxial with electromagnetic coils (50a, 50b).

Description

Specification

Electromagnetic pump

Technical field

The present invention relates to an electromagnetic pump, and more particularly, to a compact electromagnetic pump used for transporting fluids such as gas and liquid. Background art

[0002] The present applicant first accommodates a movable member made of a magnetic material in a cylinder chamber on the stator side in a reciprocating manner, and energizes an electromagnetic coil fitted around the cylinder to thereby move the movable member in the moving direction. In one of the pump chambers formed between both side surfaces and both end surfaces of the cylinder, in one of the pump chambers, fluid is sucked in from the outside through the first valve, fluid is sent out through the second valve, and the other is pumped out. We have proposed a compact and thin electromagnetic pump that performs the same pumping action in the pump room. (See Patent Document 1). In FIG. 11, the magnetic flux generated from the N pole of the magnet 103 of the mover 101 returns to the S pole of the magnet 103 via the inner yoke 104a, the outer yoke 105, and the inner yoke 104b of the stator 102. A circuit is formed. When the electromagnetic coils 106a and 106b are energized, the electromagnetic coils 106a and 106b receive the electromagnetic force S from the above-described magnetic field, and the electromagnetic coils 106a and 106b are fixed to the stator 102 side. The mover 101 moves in the axial direction of the cylinder (the vertical direction in FIG. 11).

Patent Document 1: Japanese Patent Application No. 2002-286188 In the above-mentioned electromagnetic pump, whether or not the movable element 101 accommodated in the cylinder portion 109 whose both ends are closed by the upper frame body 107 and the lower frame body 108 is operating normally. Various methods are conceivable as a method for detecting the operation of the mover, such as whether the force \ or the mover 101 is operating in an appropriate movable range. As an example of a method of detecting the operation of the mover 101, a magnetic sensor (such as a Hall element) 110 is provided outside the lower frame body 108 as shown in FIG. The magnetic sensor 110 can detect the movable position of the mover 101 by detecting the leakage magnetic flux generated from the magnet 103 of the mover 101.

Disclosure of the invention Problems the invention is trying to solve

In the configuration of the mover electromagnetic pump using the magnetic sensor shown in FIG. 11, since the mover 101 is housed in the cylinder portion 109 closed by the upper and lower frame bodies 107 and 108, the mover 101 is located near the mover 101. The magnetic sensor 110 cannot be placed. In addition, when the magnetic flux is leaked from the mover 101 and the magnetic sensor 110 is provided at a position distant from the mover 101, the size of the device is increased, and the magnetic flux density detected by the magnetic sensor 110 is further reduced. It is difficult to detect changes in the data. More specifically, when the magnetic sensor 110 is installed on one side of the upper and lower frame members 107 and 108, the magnetic flux density of the magnetic sensor 110 always changes in the same direction. The sensitivity is limited.

Further, the magnetic sensor 110 is easily affected by a magnetic field generated by energizing the electromagnetic coils 106a and 106b. That is, the cycle of the reciprocating motion of the mover 101 is the same as the cycle of the change in the magnetic flux density of the leakage magnetic flux of the mover 101. Also, the excitation cycle by energizing the electromagnetic coil is the same. Therefore, it is difficult to determine whether the change in the magnetic flux density detected by the magnetic sensor is due to the reciprocating movement of the mover 101 or the excitation of the electromagnetic coils 106a and 106b.

The present invention has been made to solve these problems, and its purpose is to accurately detect the operating position of the mover without increasing the size of the device, and to reduce the magnetic field generated by energizing the electromagnetic coil. It is to provide an electromagnetic pump which is hardly affected.

The present invention has the following configuration to achieve the above object.

A mover with a permanent magnet is housed in the cylinder, and the mover is reciprocated in the axial direction within the cylinder by energizing an air-core electromagnetic coil fitted around the cylinder to form the mover in the cylinder. An electromagnetic pump that transports a fluid from a pump chamber, wherein an air-core detection coil that detects the reciprocating motion of the mover is fitted around the cylinder coaxially with the electromagnetic coil. .

A plurality of electromagnetic coils are fitted around the cylinder, and a detection coil is fitted adjacent to both end faces in the axial direction of the electromagnetic coil.

In addition, a yoke made of a magnetic material is provided on both end surfaces in the axial direction of the detection coil, or on both end surfaces and the outer peripheral surface. In addition, the frequency of the induced voltage of the detection coil is twice the reciprocating frequency of the mover.

Further, the flow rate of the pump is detected based on the induced voltage detected by the detection coil. In this case, a threshold may be set based on the induced voltage detected by the detection coil to detect whether the flow rate of the pump is greater than a certain flow rate, or based on the induced voltage detected by the detection coil. It is also acceptable to set a threshold to determine whether the mover is reciprocating normally or not, and to control the drive of the mover based on the induced voltage of the detection coil. Still good.

Further, it is desirable to detect the induced voltage of the detection coil within a detection range in which the variation of the induced voltage due to the excitation of the electromagnetic coil is small.

The invention's effect

[0004] If the above-described electromagnetic pump is used, an air-core detection coil for detecting reciprocation of the mover is coaxially fitted around the cylinder around the cylinder where the leakage flux of the mover is large. The induced voltage generated in the detection coil by the reciprocating motion of the pump can be increased, the detection accuracy can be improved, and the operation of the mover can be detected without increasing the size of the pump.

In addition, when yokes made of magnetic material are provided on both end surfaces in the axial direction and the outer peripheral surface of the detection coil, the number of magnetic fluxes interlinking with the detection coil out of the magnetic flux generated from the mover increases. The detection voltage can be increased to increase the detection sensitivity.

In addition, by setting the frequency of the induced voltage of the detection coil to twice the frequency of the reciprocating motion of the mover, the frequency of the magnetic field generated from the electromagnetic coil excited at the same frequency as the reciprocating motion of the mover is also obtained. As a result, the change in the magnetic flux density caused by the reciprocating motion of the mover and the change in the magnetic flux density caused by the excitation of the electromagnetic coil can be easily separated, and the detection accuracy can be improved.

Further, the reciprocating motion of the mover and the flow rate of the pump can be detected based on the induced voltage of the detection coil, and the drive control of the mover can also be performed.

Brief Description of Drawings

FIG. 1 is a sectional view showing a configuration of an electromagnetic pump according to the present invention. FIG. 2 is a cross-sectional view showing a configuration of a main part of the electromagnetic pump according to the first embodiment.

Garden 3] is an explanatory diagram of a state of a magnetic flux acting on a detection coil due to movement of a mover.

Garden 4] is an explanatory diagram of a state of a magnetic flux acting on a detection coil due to movement of a mover.

Garden 5] is an explanatory diagram of a state of a magnetic flux acting on a detection coil due to movement of a mover.

FIG. 6 is a cross-sectional view showing a configuration of a main part of an electromagnetic pump according to a second embodiment.

Garden 7] is a graph showing flow rate detection of the electromagnetic pump according to the third embodiment.

Garden 8] is a graph showing flow rate detection of the electromagnetic pump according to the third embodiment.

Garden 9] is a graph showing operation detection of the mover of the electromagnetic pump according to the fourth embodiment. Garden 10] is a graph showing the operation detection of the mover of the electromagnetic pump according to the fourth embodiment.

FIG. 11 is a partial cross-sectional view showing operation detection of a conventional mover.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, the best mode of an electromagnetic pump according to the present invention will be described in detail with reference to the accompanying drawings. The electromagnetic pump according to the present embodiment accommodates a mover having a permanent magnet in a cylinder, and energizes an air-core electromagnetic coil fitted around the cylinder to move the mover in the axial direction in the cylinder. The present invention can be widely applied to an electromagnetic pump that reciprocates and transports a fluid from a pump chamber formed in a cylinder.

In FIG. 1, a typical configuration of the electromagnetic pump will be described. The mover 10 is housed in a closed cylinder and provided so as to be able to reciprocate in the axial direction of the cylinder. The mover 10 is composed of a magnet 12 formed in a disk shape and a pair of inner yokes 14a and 14b sandwiching the magnet 12 in the thickness direction. The magnet 12 is a permanent magnet magnetized in the thickness direction (vertical direction in FIG. 1) with one surface being an N pole and the other surface being an S pole. The inner yokes 14a and 14b are formed of a magnetic material, and the inner yokes 14a and 14b are each formed into a flat plate portion 15a having a diameter slightly larger than the magnet 12 and a short tube standing on the peripheral portion of the flat plate portion 15a. And a flange portion 15b. The outer peripheral surface of the flange portion 15b serves as a magnetic flux acting surface on the mover 10 side of the magnetic flux generated from the magnet 12.

The sealing material 16 is a non-magnetic material such as plastic that covers the outer peripheral side surface of the magnet 12. The sealing material 16 covers the magnet 12 so as not to be exposed to the outside so that the magnet 12 does not expand, and acts to integrally form the magnet 12 and the inner yokes 14a and 14b. Have The sealing material 16 is a force provided so as to fill the outer peripheral side surface of the magnet 12 sandwiched between the inner yokes 14a and 14b. The outer diameter of the sealing material 16 is slightly smaller than the outer diameter of the inner yokes 14a and 14b. Is formed. By forming the sealing material 16 in this way, when finishing the outer peripheral surfaces of the inner yokes 14a and 14b, the sealing material 16 does not contact the grinding blade, and the work can be performed without damaging the grinding blade. Advantages and when the thermal expansion coefficient of the sealing material 16 is larger than the thermal expansion coefficient of the inner yokes 14a and 14b, when the pump is used in a high temperature state, the gap between the movable element 10 and the cylinder becomes larger. There is an advantage in that the pump can be prevented from being reduced or lost due to thermal expansion and can be operated stably.

Next, the configuration of the electromagnetic pump on the stator side will be described with reference to FIG. A cylindrical cylinder is formed by combining an upper frame body 20a and a lower frame body 20b made of a pair of non-magnetic materials, and the above-described mover 10 is housed in the cylinder so as to be able to reciprocate. In the present embodiment, a cylinder portion 24 formed in a cylindrical shape is formed on the frame body 22b of the lower frame body 20b. By fitting the end of the cylinder portion 24 into the fitting groove 28 provided in the frame body 22a of the upper frame body 20a, a cylinder having both axial end faces closed by the pair of frame bodies 20a and 20b is formed. You. A sealing material 29 is provided at a portion of the fitting groove 28 where the end surface of the cylinder portion 24 contacts, and the inside of the cylinder is sealed from the outside by abutting the end surface of the cylinder portion 24 against the sealing material 29. The cylinder portion 24 can be extended from the upper frame body 20a and fitted to the lower frame body 20b. Further, the cylinder portion 24 may be formed separately from the upper frame body 20a and the lower frame body 20b.

As described above, both end surfaces of the cylinder are closed by the upper frame body 20a and the lower frame body 20b, and the pump chambers 30a, 30b force formed. The pump chambers 30a and 30b correspond to gaps formed between the end faces of the mover 10 and the frame body 22a of the upper frame 20a and the frame body 22b of the lower frame 20b. The mover 10 slides in a state in which the mover 10 is in air-tight or liquid-tight seal with the cylinder portion 24 while in contact with the inner surface of the cylinder portion 24. In order to improve the sliding properties of the mover 10, the outer surfaces of the inner yokes 14a and 14b have a fluororesin coating.DLC (diamond 'like' carbon) coating etc. provide both lubricity and protection. Apply the coating obtained. In addition, a detent that prevents the mover 10 from rotating in the circumferential direction can be provided.

Dampers 32 are attached to the end faces (inner wall surfaces) of the frame bodies 22a and 22b. The damper 32 is provided to absorb the impact when the inner yokes 14a, 14b abut on the end faces of the frame bodies 22a, 22b at the end position of the movable range of the mover 10. The damper 32 may be provided on the end faces of the inner yokes 14a and 14b, which are in contact with the frame bodies 22a and 22b, instead of the force provided on the end faces of the frame bodies 22a and 22b.

A suction valve 34a and a delivery valve 36a are provided in the frame body 22a of the upper frame 20a in communication with the pump chamber 30a. A suction valve 34b and a delivery valve 36b are provided in the frame main body 22b of the lower frame 20b so as to communicate with the pump chamber 30b.

The upper frame 20a and the lower frame 20b are provided with suction channels 38a, 38b which are in communication with the suction valves 34a, 34b. The upper frame 20a and the lower frame 20b are provided with delivery channels 40a, 40b communicating with the delivery valves 36a, 36b. The suction flow path 38a of the upper frame 20a and the suction flow path 38b of the lower frame 20b are connected by a communication pipe 42, and the delivery flow path 40a of the upper frame 20a and the delivery flow path 40b of the lower frame 20b. Are connected by a communication pipe 44. Thereby, the suction channel and the delivery channel of the upper frame 20a and the lower frame 20b communicate with one suction port 38 and one delivery port 40, respectively.

In FIG. 1, air-core electromagnetic coils 50a and 50b are fitted around the cylinder. The electromagnetic coils 50a and 50b are slightly spaced apart in the axial direction of the cylinder, and are arranged at an equal position with respect to the center position in the axial direction of the cylinder. The electromagnetic coils 50a and 50b are set to have an axial length longer than the movable range of the flange portion 15b of the inner yokes 14a and 14b. The winding directions of the electromagnetic coil 50a and the electromagnetic coil 50b are opposite to each other, and the currents are set to flow in opposite directions when energized by the same power supply. The reason why the winding directions of the electromagnetic coils 50a, 50b are reversed is that the force acting on the current flowing through the electromagnetic coils 50a, 50b interlinking with the magnetic flux of the magnet 12 is superimposed, and as a reaction force, And this force becomes thrust.

The outer yoke 52 is provided in a cylindrical shape so as to surround the outer periphery of the electromagnetic coils 50a and 50b. The The outer yoke 52 is made of a magnetic material, and is provided to increase the number of magnetic fluxes linked to the electromagnetic coils 50a and 50b to effectively apply an electromagnetic force to the mover 10. In addition, since the flange 15b is provided in the periphery of the inner yokes 14a and 14b constituting the movable element 10 so as to rise in the axial direction, the magnetic flux generated from the magnet 12 is transferred from the inner yokes 14a and 14b to the outer yoke 52a. , The magnetic resistance of the magnetic circuit can be reduced.

This increases the total magnetic flux acting from the mover 10 (secures a magnetic path) and causes the magnetic flux generated by the magnet 12 to interlink with the current flowing through the electromagnetic coils 50a and 50b at right angles to the axial direction. Thus, thrust in the axial direction can be effectively generated on the mover 10. Further, since the mass of the mover 10 according to this configuration is lighter than the generated thrust, a high-speed response is possible, and the output flow rate can be increased.

The electromagnetic coils 50a, 50b and the outer yoke 52 are formed by fitting the outer yoke 52 into the fitting grooves 28 provided in the upper frame 20a and the lower frame 20b when the upper frame 20a and the lower frame 20b are combined. Can be assembled concentrically with part 24. The mover 10 is reciprocally driven (moves up and down) by the action of the electromagnetic force generated by the electromagnetic coils 50a and 50b by applying an alternating current to the electromagnetic coils 50a and 50b. The electromagnetic force generated by the electromagnetic coils 50a and 50b pushes the mover 10 in one direction and the other direction depending on the direction of current supply to the electromagnetic coils 50a and 50b. By controlling the time and the energizing direction, the mover 10 can be reciprocally driven with an appropriate stroke. When the mover 10 contacts the inner surfaces of the frame bodies 22a and 22b, the impact can be absorbed by the action of the damper 32.

The pumping action of the electromagnetic pump of the present embodiment is performed by the fluid being alternately sucked into the pump chambers 30a and 30b and sent out by reciprocating the mover 10 by the electromagnetic coils 50a and 50b. That is, when the mover 10 moves downward in the state of FIG. 1, fluid is introduced into one pump chamber 30a, and fluid is simultaneously sent out from the other pump chamber 30b. Conversely, when the mover 10 moves upward, fluid is sent from one pump chamber 30a and fluid is introduced into the other pump chamber 30b. Thus, when the mover 10 moves to either side, the fluid is sucked and exhausted, the pulsation of the fluid is suppressed, and the fluid can be transported efficiently. The electromagnetic pump according to the present embodiment is configured such that inner needles 14a and 14b each having a flange portion 15b are attached to the movable element 10, and the suction valves 34a and 34b and the delivery valve 36a are provided near both end faces of the movable element 10. And 36b, it was possible to provide an extremely thin and small pump. In the case of the electromagnetic pump of the embodiment, it can be formed into a small pump having a height of about 15 mm and a width of about 20 mm.

Further, the electromagnetic pump of the present embodiment can be used for transporting gas or liquid, and the type of fluid is not limited. When using as a liquid pump, if the transport pressure is insufficient when only one mover 10 is used, a multistage type in which a plurality of unit movers of the same shape consisting of a magnet 12 and inner yokes 14a and 14b are connected. If you use mover 10, By connecting the unit movers in multiple stages, a mover having a large thrust can be obtained, and an electromagnetic pump having a required transport pressure can be obtained.

Example 1

Next, a preferred embodiment of the configuration and the detecting operation of the reciprocating operation detector of the mover of the above-described electromagnetic pump will be described with reference to FIGS. In FIG. 2, an air-core detection coil 53 for detecting reciprocation of the mover 10 is fitted around the cylinder coaxially with the electromagnetic coils 50a and 50b. Specifically, the detection coil 53 is fitted around the cylinder adjacent to both end surfaces in the axial direction of the electromagnetic coil 50a and the electromagnetic coil 50b.

FIGS. 3 to 5 show the state of magnetic flux acting on the detection coil 53 according to the operating position of the mover 10 when the mover 10 reciprocates. 3 shows a state in which the mover 10 has been displaced upward in the movable range, FIG. 4 shows a state in which the mover 10 has been displaced to the center, and FIG. 5 shows a state in which the mover 10 has been displaced downward. The amount of magnetic flux linked to the detection coil 53 becomes maximum when the mover 10 is displaced to the center of the movable range (the state in FIG. 4), and when the mover 10 is displaced upward or downward (see FIGS. 3 and 5). In the state). The mover 10 repeats the reciprocating operation in the order of FIG. 3 → FIG. 4 → FIG. 5 → FIG. 4 → FIG. During one reciprocation of the mover 10, the amount of magnetic flux passing through the detection coil 53 increases and decreases in two cycles. Therefore, the induced pressure generated in the detection coil 53 also occurs for two cycles. The detection operation by the detection coil 53 may be performed only while the mover 10 moves between FIGS. 3 and 4 or only while the mover 10 moves between FIGS. 4 and 5. good. In this case, the armature 10 emits to the detection coil 53 during one reciprocation. The generated induced voltage is one cycle. In addition, the mover 10 may have the inner yokes 14a and 14b omitted.

Example 2

Next, another example of the reciprocating motion detecting section of the mover of the electromagnetic pump will be described with reference to FIG. The same members as those in FIG. 2 are denoted by the same reference numerals, and the description is used. In FIG. 6, the detection coil 53 is the same in that it is fitted around the cylinder so as to be adjacent to both axial end faces of the electromagnetic coil 50a and the electromagnetic coil 50b. In this embodiment, yokes 26 a and 26 b made of a magnetic material are provided on both end surfaces in the axial direction of the detection coil 53, and an filter yoke 52 is provided on the outer peripheral surface of the detection coil 53. As a result, a magnetic circuit is formed in which the magnetic flux generated from the mover 10 passes through the yoke 26a, the outer yoke 52, and the yoke 26b. As a result, the number of magnetic fluxes interlinking with the detection coil 53 among the magnetic fluxes generated from the movable element 10 increases, so that the induced voltage value generated in the detection coil 52 can be increased to improve the detection sensitivity. In addition, if the yokes 26a and 26b are provided on both end surfaces in the axial direction of the detection coil 53, the outer work 52 can be omitted.

Example 3

Next, an application example based on detection of the reciprocating operation of the mover of the electromagnetic pump will be described with reference to FIGS. 7 and 8. The same members as those in FIG. 2 are denoted by the same reference numerals, and the description is referred to. The present embodiment is characterized in that the flow rate of the pump is detected based on the induced voltage detected by the detection coil 53. That is, the flow rate of the pump is the product of the speed V at which the mover 10 reciprocates and the cross-sectional area S of the mover 10. If the speed V at which the mover 10 reciprocates increases, the flow rate of the pump increases and the induced voltage of the detection coil also increases. Accordingly, in FIG. 7, the force S for estimating the flow rate of the pump can be obtained based on the magnitude of the amplitude of the induced voltage generated in the detection coil 53.

In FIG. 8, it is also possible to determine whether or not the mover 10 is reciprocating by setting a threshold based on the induced voltage detected by the detection coil 53. That is, a threshold voltage corresponding to a constant flow rate is set for the induced voltage of the detection coil 53. Then, the detected induced voltage and the threshold voltage are compared by a comparator circuit or the like and converted into a pulse output. A pulse is generated if the flow rate is higher than a certain value, and a pulse is generated if the flow rate is lower than a certain value. No noise occurs. Also, when voltage, current, frequency, etc. are applied to the electromagnetic coils 50a, 50b from the control unit under certain conditions, the upper limit of the amplitude range of the induced voltage of the detection coil 53 when the mover 10 operates normally or By setting the lower limit to the threshold voltage, it is possible to detect whether or not the mover 10 of the pump is operating normally.

Example 4

Next, an application example based on detection of the reciprocating operation of the mover of the electromagnetic pump will be described with reference to FIGS. The same members as those in FIG. 2 are denoted by the same reference numerals, and the description is referred to. The present embodiment is characterized in that the drive control of the mover 10 is performed based on the induced voltage detected by the detection coil 53. That is, by performing feedback control with a control unit (not shown) so that the mover 10 operates normally, the amount of electricity to the electromagnetic coils 50a and 50b can be controlled, the pump flow rate can be controlled, The movable range of the mover 10 can be controlled so as not to hit the upper and lower frame bodies 22a and 22b.

Further, it is desirable to detect the induced voltage of the detection coil in a detection voltage range where the fluctuation of the induced voltage due to the excitation of the electromagnetic coils 50a and 50b is small. Above and below the detection coil 53, there are electromagnetic coils 50a, 50b force S, and an induced voltage is generated in the detection coil 53 by changing the current of the electromagnetic coils 50a, 50b. FIG. 9 shows a graph of the induced voltage of the detection coil 53 including the influence of the current change amount of the electromagnetic coils 50a and 50b. Immediately after switching the excitation direction of the electromagnetic coils 50a and 50b, the amount of change in the current value with respect to time has a large effect on the induced voltage of the detection coil 53. Therefore, when the amount of change in the current of the electromagnetic coils 50a and 50b is small, that is, when the induced voltage generated by the reciprocating motion of the mover 10 is on the negative side in FIG. By providing a voltage threshold in section B), it is possible to reduce the influence of the current change in the electromagnetic coils 50a and 50b. In Fig. 9, if the amount of change in the current of the electromagnetic coils 50a and 50b in the parts A and B is large, the average value of the induced voltages in the parts A and B is calculated, and the pulse width of the parts A and B is calculated. May be detected and the average value thereof may be calculated, or only the frequency component of the induced voltage of the detection coil 53 (two times the reciprocating frequency of the mover 10) may be detected.

FIG. 9 shows the case where the frequency of the induced voltage of the detection coil 53 is twice the frequency of the reciprocating motion of the mover 10, but the frequency is the same. The induced voltage of the detection coil 53 is C and D Since the force that peaks at the portion is similarly affected by the current change of the electromagnetic coils 50a and 50b, it is difficult to detect whether the reciprocating motion of the mover 10 is appropriate. Therefore, it can be seen that by setting the frequency of the induced voltage of the detection coil 53 to twice the frequency of the reciprocating motion of the mover 10, it becomes easier to detect the suitability of the reciprocating motion of the mover 10.

The electromagnetic pump shown in FIG. 1 communicates with suction passages 38a and 38b provided on one side and the other side of the mover 10, and has a delivery pump provided on one side and the other side of the mover 10. A plurality of electromagnetic pumps, which is an example in which the flow paths are communicated in parallel, that is, the flow paths are communicated in parallel, can be used by connecting the flow paths in series. In this case, the delivery channel 40a may be connected to the suction channel 38b, or the delivery channel 40b may be connected to the suction channel 38a.

Claims

The scope of the claims

[1] A movable element having a permanent magnet is accommodated in a cylinder, and the movable element is reciprocated in the axial direction within the cylinder by energizing an air-core electromagnetic coil fitted around the cylinder. An electromagnetic pump for transporting a fluid from a pump chamber formed therein, wherein an air-core detection coil for detecting reciprocating motion of the mover is fitted around the cylinder coaxially with the electromagnetic coil. And an electromagnetic pump.

2. The electromagnetic pump according to claim 1, wherein a plurality of electromagnetic coils are fitted around the cylinder, and detection coils are fitted adjacent to both end surfaces in the axial direction of the electromagnetic coil.

3. The electromagnetic pump according to claim 1, wherein a shock made of a magnetic material is provided on both end surfaces in the axial direction of the detection coil, or on both end surfaces and an outer peripheral surface.

4. The electromagnetic pump according to claim 1, wherein the frequency force of the induced voltage of the detection coil is twice the reciprocating frequency of the mover.

[5] The electromagnetic pump according to claim 1, wherein the flow rate of the pump is detected based on the induced voltage detected by the detection coil.

6. The electromagnetic pump according to claim 1, wherein a threshold value is set based on the induced voltage detected by the detection coil to detect whether or not the flow rate of the pump is greater than a predetermined flow rate.

7. The electromagnetic pump according to claim 1, wherein a threshold is set based on the induced voltage detected by the detection coil to determine whether or not the mover is normally reciprocating.

[8] The electromagnetic pump according to claim 1, wherein drive control of the mover is performed based on an induced voltage of the detection coil.

9. The electromagnetic pump according to claim 1, wherein the induced pressure of the detection coil is detected in a detection range in which a variation in the induced voltage caused by the excitation of the electromagnetic coil is small.